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The fossil tabanids (Diptera Tabanidae): when they began to appreciate warm blood and when they began transmit diseases?

A discussion of the known fossil tabanids (Diptera Tabanidae) is presented based on fossil evidence. This includes the origin of the hemathophagy in the Brachycera, more specifically for tabanids. Several tabanid species in the extant fauna are vectors for disease-producing organisms that affect humans and animals. Bacteria, viruses, rickettsiae, protozoa, and filarial worms can be transmitted by them, causing such diseases as anthrax, tularemia, anaplasmosis, various forms of trypanosomiasis, Q fever, and filariasis. However, if tabanids are directly responsible for all of these diseases is not consensual and the known fossil evidence is presented here.

Animals↗

Natural enemies of the gall-maker Eugeniamyia dispar (Diptera, Cecidomyiidae): predatory ants and parasitoids.

Natural enemies of the gall maker Eugeniamyia dispar (Diptera: Cecidomyiidae) were studied on the urban area of Porto Alegre, RS, Brazil from October 1993 to March 1996. Galls and associated arthropods were followed weekly in the field on individual host plants (Eugenia uniflora, Myrtaceae) and also in the laboratory. Three species of ants attacked the galls, the most common being Pseudomyrmex sp. A proportion of galls was parasitised by Rileya sp. (Eurytomidae). The adults of this solitary ectoparasitoid were also attacked by the ants and fell prey to spider webs.

Animals↗

Life history of the gall-maker Eugeniamyia dispar Maia, Mendonça-Jr. & Romanowski, 1996 (Diptera, Cecidomyiidae).

The development of the galls of the midge Eugeniamyia dispar Maia, Mendonça-Jr. & Romanowski, 1996 (Diptera: Cecidomyiidae) was monitored weekly on its host plant, Eugenia uniflora (Myrtaceae). The work was carried out in the urban area of Porto Alegre, RS, Brazil, from October 1993 to September 1995. Galls were collected from the field and raised in the laboratory to obtain adults. The females oviposit on young leaves of the host plant, with the first instar larvae inducing the gall, which is unilocular. The last instar larvae drop to the soil to pupate and later emerge as adults. The galls occur from late August to early June, when young leaves of the host can be found, with populations peaking during the summer. So far this species is only known from the two southernmost states of Brazil (RS and SC).

Animals↗

Aphaereta sp. (Hymenoptera: Braconidae: Alysiinae) as a natural enemy to Peckia chrysostoma (Wiedemann) (Diptera: Sarcophagidae), in Brazil.

This paper reports the first occurence of the parasite Aphaereta sp. (Hymenoptera: Braconidae: Alysiinae) which was collected from Peckia chrysostoma pupae (Diptera: Sarcophagidae) by means of traps containing some fish baits in a wood area close to the Agronomy college (Faculdade of Agronomia) in Itumbiara, Goiás, in the period from March to September, 2001. A total of 362 gregarious specimens of parasitoids from 26 pupae of P. chrysostoma. Aphaereta sp. was collected, with several individuals emerging from the same pupae.

Animals↗

Diversity of Calliphoridae (Diptera) in Brazil's Tinguá Biological Reserve.

The Calliphoridae are flies of great ecological, medical and sanitary importance because they are decomposers of organic matter, mechanical vectors of pathogenic agents, and causers of myiasis. This paper attempts to ascertain the diversity of Calliphoridae in the Tinguá Biological Reserve and correlate meteorological data (temperature, relative humidity of the air, and precipitation) with the occurrence of these flies. The study was conducted at a site in the Tinguá Biological Reserve, located in the municipality of Nova Iguaçu, state of Rio de Janeiro, Brazil. Four traps were set up using chicken viscera as bait. The experiment was conducted over the period of May 2001 to April 2002, with two monthly collections. The captured flies were killed with ether and conserved in 70% alcohol and identified in the Laboratory of Diptera Studies (UNIRIO) and the Laboratory of Vector Insect Biology and Control (FIOCRUZ), both headquartered in the city of Rio de Janeiro, RJ, Brazil. A total of 1,987 insects were captured, 37.5% belonging to the family Calliphoridae, 29.4% to Muscidae, 16.0% to Sarcophagidae, and 17.1% to other families. The most representative species found was Phaenicia eximia (47.0%), followed by Hemilucilia semidiaphana (23.6%), Mesembrinella bellardiana (13.7%), Hemilucilia segmentaria (7.5%), Chloroprocta idioidea (4.9%), Chrysomya albiceps (1.2%), Chrysomya megacephala (0.9%), Phaenicia sericata (0.6%), Eumesembrinella sp. (0.5%), and Chrysomya putoria (0.1%). Large numbers of Calliphoridae were noted in May, June, September and January, coinciding with low rainfall and an average temperature of 21.8 to 27.0 degrees C. A negative correlation was found between the number of Calliphoridae captured and meteorological factors.

Animals↗

Postlarval fitness of transgenic strains of Cochliomyia hominivorax (Diptera: Calliphoridae).

Eight transgenic strains of Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae) were compared with the wild-type parental laboratory strain (P95) in colony. Measurements of average weight of pupae, percentage of adults emerging from pupae, ratio of males to total emerged adults, and mating competitiveness were analyzed. The parental strain colony was subcultured and exposed to handling procedures equivalent to transgenic strains for valid comparison of overall colony fitness. None of the transgenic colonies exhibited significantly lower fitness characteristics than the control parental colony. One transgenic colony had a higher ratio of adults emerging from pupae, and five colonies had higher average pupal weight; because fitness cost would only be indicated by lower values, the statistical variations were not significant. Males of one transgenic strain were shown to mate with equal frequency compared with males of the parental strain. Hence, the presence of the transgene used to produce the strains tested did not incur a fitness cost to the colonies of laboratory-reared C. hominivorax.

Animals↗

Quality of transgenic laboratory strains of Cochliomyia hominivorax (Diptera: Calliphoridae).

Genetically modified, mass reared insects present novel possibilities for the future of insect control. One concern about manipulation of insects is a possible loss of strain quality due to the introduction of a foreign gene of any sort into the insect genome. Eight transgenic strains of screwworm, Cochliomyia hominivorax (Coquerel) (Diptera: Calliphoridae), were compared with the wild-type parental laboratory strain in laboratory culture. Measurements of average fertility, fecundity, larval productivity, and longevity were analyzed. Two transgenic strains had significantly lower larval productivity than controls, one of which was explained by a homozygous lethal insertion of the transgene. Another strain produced significantly fewer eggs than controls. Overall strain characteristics, including measurements from egg, larva, pupa, and adult stages, were compared. Transgenic colonies did not consistently show significantly lower individual or aggregate strain quality characteristics than the control parental colony; hence, the presence of the transgene used to produce the strains tested did not incur a discrete cost to the colonies of laboratory-reared C. hominivorax.

Animals↗

Development of Pseudacteon nocens (Diptera: Phoridae) on Solenopsis invicta and Solenopsis richteri fire ants (Hymenoptera: Formicidae).

We studied the developmental performance of the large morph of Pseudacteon nocens Borgmeier (Diptera: Phoridae), a prospective biological control agent of imported fire ants (Hymenoptera: Formicidae). We measured selected life history traits of this parasitoid as a function of 1) host species (Solenopsis invicta Buren versus Solenopsis richteri Forel), 2) temperature (22 versus 28 degrees C), 3) source population of the fly (Corrientes and Santiago del Estero, Argentina), and 4) varied size distributions of offered host ants. Developmental periods were influenced by host species, although the populations responded in opposing manners. Developmental times, however, were most strongly influenced by temperature with total developmental periods lengthened by 17-32% at 22 degrees C. Pupal mortality was also significantly lower at this temperature. Although numbers of progeny per female were significantly higher for the Corrientes population, we found no significant differences in progeny per female according to host species. Interestingly, we found that females were larger than males, and flies from Corrientes were larger than those from Santiago del Estero, even after statistical adjustments for host size. The modal frequency of host size elected in all treatment combinations tested was identical (0.6 mm), a size that represented the apparent threshold for producing female progeny. These laboratory and additional field observations demonstrate considerable interpopulational variation in P. nocens and lend further support to the applied approach focusing at the population, as opposed to the species level, with respect to both source and target areas for classical biological control introductions of Pseudacteon flies.

Animals↗

Susceptibility of pest Nezara viridula (Heteroptera: Pentatomidae) and parasitoid Trichopoda pennipes (Diptera: Tachinidae) to selected insecticides.

Susceptibility of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), and its endoparasitoid Trichopoda pennipes (F.) (Diptera: Tachinidae) to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam was compared in residual and oral toxicity tests. In the residual toxicity test, cyfluthrin, dicrotophos, and oxamyl were highly toxic to N. viridula. Thiamethoxam was moderately toxic to these insects. Each of the four insecticides was highly toxic to T. pennipes after prolonged tarsal contact with dried residues of these chemicals. In the oral toxicity test, where N. viridula fed on food covered with insecticide residues, none of the insecticides were toxic to adults of this stink bug, but acetamiprid, dicrotophos, and thiamethoxam were moderately toxic to the nymphs. In the oral toxicity test, where N. viridula fed on a gel-food containing insecticides, cyfluthrin, dicrotophos, oxamyl, and thiamethoxam were highly toxic to this stink bug. In an oral toxicity test using contaminated sugar water, all of the insecticides were highly toxic to T. pennipes. Because insecticides were as toxic, or more toxic, to T. pennipes than to N. viridula, it is extremely important to conserve this parasitoid by applying these insecticides for control of southern green stink bugs only when the pest reaches economic threshold.

Animals↗

Improving the biological control of leafminers (Diptera: Agromyzidae) using the sterile insect technique.

The leafminer Liriomyza trifolii (Burgess) (Diptera: Agromyzidae) is a worldwide pest of ornamental and vegetable crops. The most promising nonchemical approach for controlling Liriomyza leafminers in greenhouses is regular releases of the parasitoid Diglyphus isaea (Walker) (Hymenoptera: Eulophidae). In the current study, we examine the hypothesis that the use of D. isaea for biological control of leafminers in greenhouse crops may be more practical and efficient when supplemented with additional control strategies, such as the sterile insect technique (SIT). In small cages, our SIT experiments suggest that release of sterile L. trifolii males in three sterile-to-fertile male ratios (3:1, 5:1, and 10:1) can significantly reduce the numbers of the pest offspring. In large cage experiments, when both parasitoids and sterile males were released weekly, the combined methods significantly reduced mine production and the adult leafminer population size. Moreover, a synergistic interaction effect between these two methods was found, and a model based on our observed data predicts that because of this effect, only the use of both methods can eradicate the pest population. Our study indicates that an integrated pest management approach that combines the augmentative release of the parasitoid D. isaea together with sterile leafminer males is more efficient than the use of either method alone. In addition, our results validate previous theoretical models and demonstrate synergistic control with releases of parasitoids and sterile insects.

Animals↗

Polymerase chain reaction-restriction fragment length polymorphism assays to distinguish Liriomyza huidobrensis (Diptera: Agromyzidae) from associated species on lettuce cropping systems in Italy.

The pea leafminer, Liriomyza huidobrensis (Blanchard) (Diptera: Agromyzidae), is a serious insect pest infesting open field lettuce plantings in northern Italy. In these cropping systems, it coexists with several other agromyzid species that have negligible economic importance on open field vegetables. The rapid detection of L. huidobrensis is crucial for effective management strategies, but the identification of agromyzids to species can be very difficult at adult as well at immature stages. In this study, a polymerase chain reaction (PCR)-restriction fragment length polymorphism assay is proposed to separate L. huidobrensis from Liriomyza bryoniae (Kaltenbach), Liriomyza trifolii (Burgess), and Chromatomyia horticola (Goureau), which usually occur in the same lettuce plantings. An approximately 1,031-bp region of the mitochondrial genome encompassing the 3' region of cytochrome oxidase I, the whole leucine tRNA, and all of the cytochrome oxidase II was amplified by PCR and digested using the enzymes PvuII and SnaBI separately. Both endonucleases cut the amplicons of L. huidobrensis in two fragments, whereas the original band was not cleaved in the other analyzed species. The presence of Dacnusa spp. DNA does not bias the assay, because the PCR conditions and the primer set here described do not amplify any tract of this endoparasitic wasp genome.

Animals↗

Detection of Contarinia nasturtii (Diptera: Cecidomyiidae) in New York, a new pest of cruciferous plants in the United States.

The midge Contarinia nasturtii Kieffer (Diptera: Cecidomyiidae) was first confirmed in North America in Ontario, Canada, in 2000. The insect is now distributed throughout many counties in the provinces of Ontario and Québec. Nearly 1,200 farms in the northeastern United States that grow cruciferous vegetables are at risk for C. nasturtii infestation if this insect were to spread to that region. Over a period of 3 yr (2002-2004), approximately 3,000 ha of crops on 94 farms in western New York State was scouted for C. nasturtii, but none were found. In 2004, 42 experimental pheromone traps were placed in fields of cruciferous vegetables in eight counties. C. nasturtii males were captured at low levels (1-50 per trap / 8 wk) on four farms in Niagara County, but not at any other site. C. nasturtii larvae were found in plant tissue at one of the four farms. Insect specimens were identified by morphological methods, molecular methods, or both. This is the first confirmation of C. nasturtii in the United States, which we believe was made possible by the combined use of pheromone traps, morphological characters of trapped adults, and molecular methods. The early detection in New York presents an opportunity to implement measures to limit the spread and establishment of C. nasturtii across the state and into other regions of the United States.

Animals↗

Onion maggot (Diptera: Anthomyiidae) resistance to chlorpyrifos in New York onion fields.

A larval immersion bioassay was developed to identify susceptibility of onion maggot, Delia antiqua (Meigen) (Diptera: Anthomyiidae), to chlorpyrifos and to determine whether this assay could be used to predict control in onion fields. Laboratory colonies were established from larvae collected in New York onion fields during 2003 and 2004, providing us with test insects to use in bioassays. The larval assay effectively determined susceptibility of D. antiqua to chlorpyrifos, and results were congruent with an adult bioassay. However, use of similar-aged larvae (4 d old) in the assays was critical because larvae became more tolerant to chlorpyrifos as they aged. In a field survey, six of the 13 populations had LC50 values above the recommended field rate of 3,600 ppm (range 4,031-6,869). Over two successive seasons in the same field, susceptibility of D. antiqua to chlorpyrifos decreased in two of three fields (by 45 and 42%) and remained the same in another field, indicating that resistance is not predictable from year to year. Based on the relationship between damage in the field and LC50 values from 11 of the populations mentioned above, all five populations that had LC50 values above the field rate caused unacceptable levels of damage, whereas five of six populations that had LC50 values below the field rate did not cause serious damage.

Age Factors↗

Effects of fall and spring seeding date and other agronomic factors on infestations of root maggots, Delia spp. (Diptera: Anthomyiidae), in canola.

Several agronomic benefits can result from fall seeding of canola (Brassica spp.), but extensive research data are lacking on the potential impact of this practice on infestations of root maggots (Delia spp.) (Diptera: Anthomyiidae), which are major pests of the crop in western Canada. Field experiments making up 13 location by year combinations were conducted in central Alberta, Canada, from 1998 to 2001 to determine the effect of fall versus spring seeding of canola on root maggot damage. Depending on the experiment, interactions with seeding rate, seed treatment, timing of weed removal, and canola species (cultivar) also were investigated. Root maggot damage declined with an increase in seeding rate for plots seeded in May but not in fall or April. Susceptibility to infestation was greater for plants of Brassica rapa L. than Brassica napus L., but seed treatment had no effect on damage by these pests. Combined analysis using data from all experiment by location by year combinations indicated that seeding date had no significant effect on root maggot damage. The extended emergence of Delia spp. adults, which spans the appearance of crop stages vulnerable to oviposition regardless of seeding date, prevented reduced root maggot attack. Covariance analysis demonstrated the importance of increasing seeding rate for reducing root maggot infestations, a practice that can be especially beneficial for May-seeded canola when growing conditions limit the ability of plants to compensate for root maggot damage. Results determined with the small plot studies described here should be validated in larger plots or on a commercial field scale, but both the combined and covariance analyses indicate that seeding canola in fall does not predispose plants to greater damage by larval root maggots than seeding in spring.

Agriculture↗

Fumigant activity of plant essential oils and components from Schizonepeta tenuifolia against Lycoriella ingenua (Diptera: Sciaridae).

Plant essential oils from 21 plant species were tested for their insecticidal activities against larvae of Lycoriella ingenua Dufour (Diptera: Sciaridae) by using a fumigation bioassay. Good insecticidal activity against larvae of L. ingenua was achieved with essential oils of Acorus gramineus Solander, Schizonepeta tenuifolia Briquet, and Zanthoxylum piperitum De Candolle at 25 microg/ml air. S. tenuifolia oil showed the most potent insecticidal activity among the plant essential oils. At 12.5 microg/ml air concentration, S. tenuifolia oil caused 96.6% mortality, but mortality decreased to 60% at 3.125 microg/ml air. Analysis by gas chromatography-mass spectrometry led to identification of three major compounds from S. tenuifolia oil. These three compounds were tested individually for their insecticidal activities against larvae of L. ingenua and compared with the toxicity of dichlorvos. Pulegone was the most toxic, followed by menthone and limonene with LC50 values of 1.21, 6.03, and 15.42 microg/ml, respectively. LC50 of dichlorvos was 8.13 microg/ml. Effects of S. tenuifolia and its components on growth of Pleurotus ostreatus (Jacq. ex Fr.) Kummer also were investigated.

Animals↗

Does R gene resistance allow wheat to prevent plant growth effects associated with Hessian fly (Diptera: Cecidomyiidae) attack?

Resistance genes (R genes) are an important part of the plant's immune system. Among insects, the Hessian fly, Mayetiola destructor (Say) (Diptera: Cecidomyiidae), larva is the target of the greatest number of characterized R genes (H1-H32). The biochemical/molecular mechanism of R gene resistance to Hessian fly is not well understood. In the absence of an effective R gene, larvae caused extensive growth deficits (> 30 cm) in wheat seedlings. In the presence of one of three effective R genes, H6, H9, or H13, larvae caused small growth deficits (approximately 3-4 cm) in two leaves (third and fourth) that were actively growing during the first days of larval attack. After larvae died on R gene plants, the fifth leaf and tiller leaves exhibited small increases in growth (2-4 cm). Growth responses of susceptible and resistant plants diverged at a time when Hessian fly larvae were establishing a nutritive gall tissue at feeding sites. The results of this study support the hypothesis that R gene resistance cannot prevent initial larval attack, but, by stopping the formation of the larval gall, it prevents the most serious consequences of larval attack.

Animals↗

Components of developmental plasticity in a Michigan population of Lucilia sericata (Diptera: Calliphoridae).

Forensic entomologists rely on laboratory growth data to estimate the time of blow fly colonization on human remains. Several data sets exist for the development of the common blow fly Lucilia sericata (Meigen) (Diptera: Calliphoridae), and although they generally describe similar rates of preadult development, all vary. Such differences could be explained by genetic variation, environmental (rearing) variation, or both. In the study presented here, flies from a single population were reared under variable conditions of food moisture, substrate type, substrate freshness, and sampling, to determine the effect each had on developmental time. Cohorts were tested in a single incubator at a single temperature and humidity, to eliminate effects of undesired environmental variation. Fly developmental times were significantly influenced by multiple laboratory rearing treatments; food moisture, transferring postfeeding larvae to fresh substrate, and destructive sampling affected different stages of development. Developmental times ranged from 329 to 505.5 h, covering the spectrum of variation observed in published data sets. Growth was then compared with larval development on rat carcasses under the same environmental conditions, establishing a link between laboratory-controlled growth and development on carrion. Cohorts raised on rats matured to adulthood between 333 and 337 h, which was best mimicked by the fastest growth treatment observed under laboratory conditions. The large environmental influence on development observed in this study could affect forensic entomology casework and accentuates the need for a standardized means of rearing flies in a laboratory setting that is relevant to decomposition on a corpse.

Animals↗

Evaluation of significance of bacteria in larval development of Cochliomyia macellaria (Diptera: Calliphoridae).

Bacteria were isolated and identified from the digestive tract of the secondary screwworm, Cochliomyia macellaria (F.) (Diptera: Calliphoridae), and their role in the larval development of this insect was assessed in laboratory bioassays. The analysis of 16S rDNA sequences revealed that the bacterial isolates represented four species: Providencia sp., Escherichia coli O157:H7 (Escherich), Enterococcus faecalis (Orla-Jensen), and Ochrobactrum sp. (Holmes). Developmental assays demonstrated that C. macellaria larvae are able to develop on a sterile blood agar, and no bacteria are required to complete larval development. Indeed, developmental times were shorter and survival rates of C. macellaria on a sterile blood agar and the modified Harris rearing diet were greater compared with that on the blood agar inoculated with individual and mixed bacterial isolates. The cultures of Ochrobactrum sp. and E. faecalis supported larval development to a significantly greater extent than those of Providencia sp. and E. coli O157:H7. The presence of bacteria in newly emerged C. macellaria adults also was assessed and revealed that the bacteria in the gut of larvae can survive pupation and colonize the gut of adult flies. This study shows that development of larvae of C. macellaria does not depend on bacteria and that some bacterial isolates negatively impact larval development.

Analysis of Variance↗